Press for metallic denture-backings



R. M. CRAIG. PRESS FOR METALLIC DENTURE BACKINGS.

APPLICATION FILED JULY 3, I919.

Patented Mar. 29,1921.

ZSHEETS-SHEET 1 INVENTOR:

v pansy.

R. M. CRAIG.

PRESS FOR METALLIC DENTURE BACKINGS.

APPLICATION FILED JULY 3,1919.

1,373,170. Patented Mar. 29, 1921.

2 SHEETS-SHEET 2.

INVENTOR:

ROBERT .M. CRAIG, OF WILKINSBURG, PENNSYLVANIA.

PRESS FOR METALLIC DENTURE-BACKINGS.

specification of Letters Patent. Patented M 29 1921 Application filed July 3, 1919. Serial No. 308,590.

To all whom it may concern Be it knownthat I, ROBERT M. CRAIG, a citizen of the United States, residing at Wilkinsburg, in the county of Allegheny and State'of Pennsylvania have invented a certain new and useful Improvement in Presses for Metallic Denture Backings, whereof the following is a specificatiomreferenee being had to the accompanying draw- 1H0.

It is the object of my invention to provide apress, including cooperative dies, of special construction for pressing a blank punched from an Lbar, to form a metallic backing for porcelain tooth facings of the class contemplated in Letters Patent Reissue 12,753 reissued to me February 18, 1908, which may be utilized in a plate,bridge, or other form of denture.

The process of making metallic denture backings, the metallic denture backingsproduced by that process andthe metallic denture drawing dies used in that process to form the I-barsjherein contemplated, are re spectively claimed in my copending applications for Letters Patent of the United States.

My invention includes the various novel features of construction and arrangement herein specified and claimed.

Insaid drawing; Figure I is a perspective view of press mechanism, including a set of special dies above contemplated, embodying my invention. I

Fig. II is a plan view of the mechanism shown in Fig. I, butwiththe upper plunger die removed and with a blank fitted in the blank seat between the blank holders of the lower die, in positionto be pressed.

Fig. III is a vertical central transverse sectional view of the mechanism shown in Fig. I.

Fig. IV is a vertical sectional "view, similar to Fig. III, but with said mechanism moved to the position in which said blank is pressed to form said metallic denture backin I FigV is a perspective view oftheblank shownin Fig. II. I

Fig. VI is a perspective view of the metallic denture backing, formed from said blank,as indicated in Fig. IV. I

In said figures; the backing blank 1. is of approximately rhombic outline. having its axis 2 corresponding with the longitudinal axis of the I-bar from which it has been punched; so that the major portion of its area is formed ofthethin web portion3 of said bar, only a fraction ofsaid area being formed of the thickest, edge portions, of said bar, as indicated at 4.

Referring particularly to Figs. IV and VI; it may be observed that the substantlally U-shaped metallic backing 5, formed from said blank 1, has opposite side flanges formed by the thick edges 4 aforesaid, bent so that they converge both from the bottom toward the top and from the intermediate web 3 toward the observer. Although said side flanges merge into said web directly at theupper edge of the latter; they merge into said web above the lower edge of the latter, so as to leave a downwardly projecting portion 6, which, in the completed denture, forms a locking flange for engagement with the porcelain face to prevent theaccidental escape-of thelatter from said backing. As it is intendedthatsaid flange 6 may be repeatedlv bentto permit said porcelain facing to e removed and replaced; the metal of the blank thereat must be left in such ductile condition as to permit repeated flexure, without fracturing it. That result is obtained by punching said blank 1 with dies which are so formed as to swage the thick edges 4 thereof, so as to make them slightly thinner than the corresponding portions of the Lbar, and correspondingly more rigid, without such swaging effect upon said intermediate web 3. In other words, the metal of said blank 1 is preferably of different degrees of ductility at different regions thereof, in accordance with the particular stresses to which those regions are intended to be subjected :inthe completed denture.

Referring to Figs. I to IV inclusive; 8 is the die base plate, conveniently provided with slots 9 to receive bolts by which it may be securedto thebed 10 of a suitable press. Said plate supports, independently of any such bed, the pair of lower die members 11 and 12. Said die member 11 is rigidly connected with said plate, conveniently by the cap screws 13, which extend vertically there through, in screw threaded engagement with said base plate 8. Said die member 11 also carries the two set screws 15 which may be adjusted to hold said die member 12 away from said diemember 11, at a precisely we determined, but variable, distance. Said die member 11 also carries the bolts 16 which are preferably rigidly held in said die memby the tops of said bosses 21 and 22.

ber 11, but extend through said die member 12 and are provided with respective nuts 18, whereby said die member 12 may be drawn toward said die member 11, in opposition to said set screws 15; said bolts 16 having washers 19 interposed between said nuts and said die member: I

Said die members 11 and 12 have, intermediate of their length, similar and transversely-alined semi-hexagonal bosses 21 and 22' upon which the respective blank holders 23 and 24 are adjustably secured by the screws 26 and 27, which are engaged in said bosses'but extend transversely in said holdem, as best shown in Fig. I. Said holders are provided with oppositely counterpart recesses 31 and 32, forming side walls of a blank seat, the bottom of which is formed It is to be understood that the arrangement last described is that said holders may be adjusted to receive blanks of different sizes, so that such blanks may be singly held thereby in the precise positionrequired for is wider at its edge 37 than its edge 38.

Moreover, said die member 36 has its lower face curved, as indicated at 39 in Fig. I, to impart a corresponding curvature to the intermediate web 3 of said denture backing,

' as indicated in Fig. VI. In order to insure the formation of that curvature in the backing; I provide the follower 41 which is wedge shaped like said recess between said die members 11 and 12, and preferably loosely seated therein, as indicated in Fig. II. Said follower has its upper face rounded, as indicated at 42, complementary to the curvature of the lower face of said upper die member 36.

Saidfollower '41 is preferably yieldingly supported by the follower yoke 45, which is mounted to reciprocate vertically upon the pair of bolt studs 46, which are rigidly secured in said base plate 8 .and extend freely through holes in said yoke, the upper surface of the latter, upon which said follower rests, being plane, as indicated in Figs. III and IV. Said bolt studs 46 are respectively encircled by springs 47, the lower ends of which 'rest upon the nuts 48, which are vertically adjustable upon said studs, to variably determine the pressure of said springs upon said yoke.

The mechanism above described is conveniently operated, as follows. Said base per die plunger 36 being secured in the upper, vertically reciprocatory member of said press, in position to register with the lower die members 11 and 12, as above described, and said die member 36 being at the upper range of its movement, as indicated in Fig. I; a die blank 1 is laid in the blank sea-t between said holders 23 and 24, as indicated in Fig. II, and said upper member of the press lowered to thrust said die plunger 36 downwardly to the position shown in Fig. IV. During such movement, said plunger 36 bends said blank 1 between said die members 11 and 12 and over the rounded top 42 of said follower 41: the pressure upon the latter forcing said yoke 4:) downwardly against the pressure of said springs 47, to the position shown in Fig. IV, in which the metallic backing 5 is pressed to the form shown in Fig. VI. 'lhereupon. said upper press member being raised; said springs 47 lift said yoke 4-5, and said follower 41 resting thereon. to the position shown in Fig. III, thus ejecting said completed metallic backing 5. However, said backing is detained by said die member 36, because the latter is a double wedge, not only converging from its edge 37 to its edge 38, but also converging from its lower face upwardly to its neck 48. Therefore. in order to release and remove the backing from said die member 36, it is necessary to slide the backing transversely with respect to said member. in the direction of the arrow in Fig. I. whereupon, the operation above described is repeated.

Although I find it convenient to make said lower die members 11 and 12 adjustable, by the means above described, so that backings of different dimensions may be made with the same set of such dies; I do not desire to limit myself to such an arrangement, as suitable sets of die members. respectively adapted to make different sizes of metallic backings, may be employed, embodying essential features of my invention. above described.

Therefore, I do not desire to limit myself to the precise details of construction and arrangement herein set forth, as it is obvious that various modifications may be made therein, without departing from the essential features of my invention, as defined in the appended claims.

I claim 1. In mechanism for pressing sheet metal the combination with a base plate; of a pair of complementary die members, on said base plate, having opposite complementary die recesses, forming a passage to receive the article which is pressed; means detachably rigidly connecting one of said die members in stationary relation with said base plate; means adjustably connecting the other of said die members with said stationary die a said slots in engagement with said lugs,

wherebysaid blank holders may be secured in variable relation, to hold blanks of different sizes in registry with the passage between said die members; a followerrfitted'to reciprocate in said passage,betwee n said die members; a follower yoke,ibeneath said base plate, supporting said'follower; a pair of guide bolt studs, rigidly connected with said base plate at their upper ends and extending through holes in said yoke; spiral springs respectively encircling said bolt studs, and having their upper ends bearing upon the under side of said yoke; nuts, vertically adjustable on said studs, supporting the lower ends of said springs, whereby said follower is yieldingly supported, by variable pressure of said springs; and a reciprocatory die plunger adapted to register with said follower in said passage.

2. In mechanism for pressing sheet metal; the combination with a base plate; of a pair of complementary die members, on said base plate, having opposite complementary die recesses, forming a passage to receive the article which is pressed; means adjustably connecting one of said die members with the other,including bolts having nuts arranged to draw said members together, and set screws adjustable to variably limit the approach of said members; oppositely comp ementary blank holders, respectively mounted on said die members, adjacent to said recesses; securing means whereby said holders are transversely adjustable, whereby said blank holders may be secured in variable relation, to hold blanks of different sizes in registry with the passage between said die members; a follower fitted to re ciprocate in said passage, between said die members; a follower yoke, beneath said base plate, supporting said follower; a pair of guide bolt studs, rigidly connected with said base plate at their upper ends and extending through holes in said yoke; spiral springs respectively encircling said bolt studs, whereby said follower is yieldingly supported; and a reciprocatory die plunger adapted to register with said follower in said passage.

3. In mechanism for pressing sheet metal the combination with a base plate; of a pair of complementary die members, on said base plate, having opposite complementary die recesses, forming a passage to receive the article which is pressed; independently adjustable oppositely complementary blank holders, respectively mounted on said die members, adjacentto said recesses, arranged to hold blanks of different sizes in registry withthe passage between saiddie members; a follower fitted to reciprocate in said passage, between said die members; spring means whereby said followeris yieldingly supported and a reciprocatoly die plunger adapted to register with said follower in said assage. a

a 4.? mechanism for pressin sheetmetal; the combination with abase p. late; of aipair of complementary die members, on said base plate, having ropposite complementary die recesses, forming a passage to receive the article which is pressed; a follower fitted to reciprocate in said passage, between said die members; spring means whereby said follower is yieldingly supported; and a reciprocato die plunger adapted to register with said follower 1n said passage, the lower end of said plunger being a double wedge, converging transversely and upwardly; whereby said mechanism is adapted to press a hollow article, havin a cavity which is wider inside than at t e opening through which the die member enters it.

5. In mechanism for pressin sheet metal; the combination with a base p ate; of a pair of complementary die members, on said base plate, having opposite complementary die recesses, forming a passage to receive the article which is pressed; a follower fitted to reciprocate in said passage, between said die members; spring means whereby said follower is yieldingly supported; and a reciprocator die plunger adapted to register with said follower in said passage, the lower end of said plunger being a double wedge, converging in two directions; whereby said mechanism is adapted to press a hollow article, having a cavity which is wider inside than at the opening through which the die member enters it.

6. In mechanism for pressing sheet metal; the combination with a pair of complemen tary die members, having opposite complementary die recesses, forming a passage to receive the article which is pressed; of means adjustably connecting said die members, including bolts having nuts arranged to draw said members together, and set screws adjustable to variably limit the approach of said members; oppositely complementary and relatively adjustable blank holders, respectively mounted on said die members, adjacent to said recesses, adapted to hold blanks of different sizes in registry with the passage between said die members; and a reciprocatory die plunger adapted to register with said passage.

7. In mechanism for pressing sheet metal;

the combination with a pair ofeomplementary die' members, having opposite complementary die recesses, 'forming apassage'to receive the article which is pressed; of oppositely complementary and relatively adjustablefblank holders, respectively mounted on said diemembers, adjacent to said recesses, adapted to hold blanks of different sizes in registry with the passagebetween said die members; and a 'reciprocatorydie plunger adapted to register with said passage.

8. In mechanism for pressing sheet metal;

the combination with a pair -of complementary die members, having oppositeeomplementary die recesses forming a passage to receive the article which is pressed; of oppositely complementary and relatively adjustable blank holders, respectively mounted on said die members, adjacent to said re eesses, adapted to hold blanks of different sizes 1n registry with the passage between said die members; said die members being adjustable to vary the dimensions of said passage, and said blank holders being adjustable in the same direction as said die members, but independently thereof; and a reciprocatory die plunger adapted to register with said passage.

In testimony whereof, I have hereunto signed my name at Wilkinsburg, Pennsylvania, this twelfth day of November, 1918.

ROBERT M. CRAIG. 

